Ben Whishaw, the star of Criminal Justice, is one of Britain’s most in-demand young actors. The thought-provoking drama by acclaimed British writer Peter Moffat (Cambridge Spies, North Square) is screening as a two-part series on Sunday 4 and Monday 5 October at 8.30pm on TV ONE.

The Perfume: The Story Of A Murderer and Brideshead Revisited star says he found the script of Criminal Justice instantly thrilling and hard to put down. He explains: “I started to dream about it and talk to friends about it – it got under my skin. It was something I felt I had to do, and the story seemed to tap into really primal fears. It has a nightmarish quality – it’s complex and challenging. I felt it would challenge me in big ways.

“I had to take a break between reading each episode to get my breath back and calm down,” he says. “It got me so charged. I loved the way it worked simply on the level of thriller, and yet it also felt very real, very authentic – particularly in its depiction of the politics of prison life. I was shocked and surprised and enthralled by it.”

Whishaw plays Ben Coulter, a 21-year-old with a sensitive nature and a happy-go-lucky outlook on life, who finds himself charged with murder at the end of a drug and drink-fuelled night out.

“Ben is really a kind of everyman figure – it seemed to me he could be any one of us. He’s young and open – an innocent. His story begins one fairly ordinary Saturday night when, through a series of minor events, he picks up a girl and spends the night with her and, within 24 hours, has been charged with murder. And so begins a journey that he couldn’t possibly have anticipated and, in many ways, is not equipped to cope with. It’s a test of his every resource.

“Ben’s journey is an enormous one,” continues Whishaw. “For me, it’s really a story about how you keep a good heart in a system that’s designed to break you. How do you hold on to the truth when everybody doubts you? It could be said that it’s also a story about growing up – growing from child to adult and the hard lessons that transition brings.”

Whishaw says he was intrigued by Ben’s plight. He says, director Otto Bathurst advised him to base his character, more or less, on himself. “It’s the first time I’ve approached a character in that way. I kept saying to myself: ‘Keep it simple and keep it honest’. I just had to put myself in his situation and behave the way I would behave in such a situation. I wanted the audience to feel that they were Ben, and to feel what he feels.”

He says, “Criminal Justice is a thrilling human story. It’s about somebody who is unexpectedly taken to the extremes of human experience. I think the directors, Otto (Bathurst) and Luke (Watson), have done a fantastic job of making Peter’s story exciting, and challenging, and moving. I think it may well be uncomfortable viewing at times, but sometimes it’s important to feel uncomfortable.”

Criminal Justice follows Ben’s rollercoaster ride through the criminal justice system, where the truth is optional and what counts is playing the game. No one wants to hear Ben’s side of the story – as soon as he is arrested, a complex game of cat and mouse begins, played out by his world-weary solicitor Stone (Con O’Neil, Learners) and the pugnacious DCI Box (Bill Paterson, Sea Of Souls). Ben’s shocked parents don’t know where to turn and deep down there is a terrifying doubt: their son could be a murderer.

Ben’s world becomes the labyrinth of police station, prison and courtroom. As Ben steps off the prison bus he has to learn to survive alongside cellmates and hardcore career criminals Hooch (Pete Postlethwaite, The Constant Gardener) and Freddie Graham (David Harewood, Gunrush). Lost in this alien world, Ben has little sense of where things start or finish, and who is in charge.